摘要
反应时，酸酐基首先与4’/4’’-氨基反应原位生成以AB2型酰胺酸为主要成分的中间体；当进一步提高反应温度时，3-氨基被活化，中间体可进行自缩聚，顺利得到端酸酐基超支化聚酰亚胺，而有效避免聚合过程中发生凝胶化。最终制得的端酸酐基超支化聚酰亚胺的数均分子量为：2.89-3.91 × 104、分子量分布系数为2.10-2.27；支化度为0.39-0.45；具有良好的溶解性和优异的热稳定性，有望用作线性聚酰亚胺的加工助剂。
make it happen
关键词：叔丁基，芴基，一步法高温缩聚，溶解性，聚酰亚胺，透明薄膜，超支化聚合物，B’B2型三胺单体，AB2型中间体，凝胶
SYNTHESIS AND CHARACTERATION OF SOLUBLE AND TRANSPARENT POLYIMIDES CONTAINING
TERT-BUTYL WITH HIGH GLASS TRANSITION
TEMPERATURE
ABSTRACTricecow
As a kind of high-performance polymers, polyimides posss excellent themal stability, mechanical properties, insulated properties and have been widely applied in many high-tech fields, including space flight, optoelectronic technology, composite materials and so on. However the applications of most traditional polyimides were limited becau of suffering from their inherent defects, such as poor solubility (rigid backbone), deep color and low optical transparency (Charge-transfer complex, CTC) etc. Thus various approaches have been adopted to modify the chemical structrue of polyimides and improve their solubility and transparency. But some of them (for example, introduction of flexible linkages, long alkyl chains etc. into polyimides) would damage their thermal stability and decrea their glass transition temperatures. As an effective strategy, introduction of bulky side groups into polyimides can resolve the problems to a certain extent. As a typical bulky side group, the introduction of tert-butyl has significant and distinctive effects on the physical properties of polyimides, including improving their solubility and optical properties without sacrificing the inherent thermal properties. In this disrtation, we synthesized a ries of linear and hyperbranched polyimides containing tert-butyl side groups, and the effects of tert-butyl on the synthesis and properties of polyimides were systematically studied. The main contents and conclusions are shown as follows:
1. Study on the effects of the tert-butyl number on the properties of polyimides
重山复水Two novel tert-butylated diamines, 3-tert-butyl-4,4’-diaminodiphenyl ether (1) and 3,3’-di(tert-butyl)-4,4’-diaminodiphenyl ether (2), with the same molecular backbone and different numbers of tert-butyl side groups were prepared with the Ullmann coupling reaction. They were polymerized with some commercial aromatic dianhydrides to afford two ries of polyimides with different numbers of tert-butyl per repeating unit. We characterized the polyimides by NMR, GPC, DSC, TGA, XRD, FTIR and UV-Vis spectra etc to study the effects of the tert-butyl number on the properties of polyimides. From the results we could conclude that, the solubility and transparency of polyimides incread with the number of tert-butyls, while the increa of the number of tert-butyls would slightly decrea the thermal stability of polyimides. It emed that the number of tert-butyls had little effect on the mechanical properties of polyimides. In addition, the glass transition temperature of the two ries of polyimides also incread with the number of tert-butyls.
2. Synthesis and characteration of soluble polyimides with high glass transition temperature from benzidine containing tert-butyl groups
A novel diamine monomer 3 was synthesized by introducing tert-butyl into benzidine, and veral commercial aromatic dianhydrides were polymerized with 3 to afford a ries of linear polyimides. The number-average molecular weights of the polyimides were in the range from 4.21 × 104 to 1.
25 × 105 with the polydispersity indexes (PDIs) from 2.34 to 3.04 by means of gel permeation chromatography (GPC) relative to a polystyrene standard. All the polyimides could be dissolved in common organic solvents and the corresponding flexible and tough films could be obtained by the solution-casting. The XRD results indicated that they were amorphous materials. All the polyimides possd high glass transition temperature above 330 o C except the 3-BPADA, and especially the T g of 3-BPDA could reach up to 375 o C. All of them were stable up to 450 o C under a nitrogen atmosphere, which indicated that the introduction of tert-butyl could improve their solubility, but not obviously decrea their thermal stability.
3. Synthesis and characteration of soluble and transparent polyimides from a novel diamine containing tert-butyl and fluorene units
法语专业就业前景A ries of polyimides containing tert-butyl and fluorene units were prepared through the polymerization of veral commercial aromatic dianhydrides and a novel diamine monomer 4, which was synthesized through the condensation reaction of 9-fluorenone and
2-tert-butylaniline. The number-average molecular weights of the polyimides ranged from 4.54 × 104 to 8.82 × 104 with the polydispersity indexes between 2.51 and 4.33 by means of GPC relative t
o a polystyrene standard. All the polyimides displayed high solubility in common organic solvents and tough films could be prepared by solution-casting. The films (about 15 μm thickness) exhibited high optical transparency above 90% in a wavelength range of 400-700 nm by UV-Vis measurement, which were far higher than the traditional aromatic polyimide PMDA-ODA. And the colors of them were also relatively lower than that of the PMDA-ODA. In conclusion, the introduction of the side groups tert-butyl and fluorene unit into polyimides could enhance the optical transparency of polyimide films, which guarantee them as potential candidates for optical applications.
4. Application of stereo-hindrance effect of tert-butyl in the synthesis of hyperbranched polyimides
A novel B’B2-type triamine, N1,N1-bis(4-aminophenyl)-4-(tert-butyl)benzene-1,3- diamine (5) was synthesized through the introduction of tert-butyl into the ortho positon of 3-amino of N1,N1-bis(4-aminophenyl)benzene-1,3-diamine. Due to the stereo-hindrance effect, the reactivity of 3-amino group in triamine 5with the ortho-tert-butyl group is much lower than tho of 4’/4’’ -amino groups at 20 o C. Therefore, when 5 (B’B2) was polymerized with dianhydrides (A2) with the molar ratio of 5:dianhydrides 1:2 at 20 o C, the dianhydrides would react with the 4’/4’’ -amino lectively to form the AB2-type intermediate in situ. And with increasing the reaction temperature, 3-amino group with ortho-tert-butyl group is activated and polycondend with anhydride groups in AB2-type intermediat
guees rapidly to afford the hyperbranched polyimide (HBPI) with terminal anhydrides and high DB. As expected, no gelation is formed in the polymerization process. The number-average molecular weights of the HBPIs ranged from 2.89 to 3.91 ×104 with PDIs from 2.10 to 2.27 and DBs from 0.39 to 0.45. All the HBPIs displayed excellent solubility and thermal properties.
Key words: tert-Butyl; Fluorene unit; Glass transition temperature; One-pot high temperature polycondensation; Solubility; Transparent films; Hyperbranched polymer; B’B2-type triamine monomer; AB2-type intermediate; Gelation.
目录
目录
摘要.......................................................................................................................... IV 目录.......................................................................................................................... I 缩写说明.................................................................................................................... I 第一章绪论 . (1)
1.1聚酰亚胺概述 (1)
1.2聚酰亚胺的合成 (3)
beneath the glory1.2.1 二酐和二胺缩聚 (3)
1.2.2 四酸或四酸二酯和二胺缩聚 (4)
1.2.3 二酐和二异氰酸酯缩聚 (5)
1.2.4 二酐和硅烷化二胺缩聚 (5)
1.2.5 二硫酐和二胺缩聚 (6)
1.2.6 采用Diels-Alder反应制备聚酰亚胺 (6)
1.2.7 利用取代或偶联反应制备聚酰亚胺 (8)马尔克斯去世
1.3 可溶性高透明聚酰亚胺的制备 (9)
1.3.1 引入柔性连接基团 (10)
1.3.2 引入脂环 (13)
1.3.3 引入不对称结构 (13)
1.3.4 引入侧基 (15)
lol是什么意思1.4 引入不同侧基的聚酰亚胺 (15)
1.4.1 引入卤素及卤代烃基 (16)
1.4.2 引入脂肪族侧基 (18)
1.4.3 引入芳香族和芳杂环侧基 (20)
1.5 引入叔丁基侧基的聚酰亚胺 (22)
1.6 超支化聚酰亚胺 (24)
1.6.1 通过AB2型单体自缩聚制备超支化聚酰亚胺 (25)
1.6.2 通过A2+B3型单体合成超支化聚酰亚胺 (27)
skirts
1.7 本论文的选题意义及研究内容 (29)
hats第二章实验部分 (31)
